Project III is a 4-year (K-G3) longitudinal study of the classroom instructional context of English-language learners (ELLs) in 144 classrooms in urban Texas, border Texas, and urban California. The central question is: Within and across language programs, what instructional strategies are used in Spanish and in English, and how do they relate to student literacy development? Three specific aims are proposed to address this central question. (a) description of classroom instruction; (b) linking of classroom instructional data to student growth and outcomes in literacy; and (c) the development of teacher knowledge. Project III will provide extensive in depth observations of classrooms according to a time-sampling procedure of reading/language arts instruction developed in our NICHD early interventions projects involving 1600 children in grades K-4 in Houston and Washington, D.C. schools. To address the first specific aim, we will quantify the ratio of English to Spanish spoken by teachers and students so that we can examine the extent to which the ratio varies within and across language programs of immersion, early transition, late transition, and dual language. We will also code reading/language arts instruction with respect to the amount and quality of time spent on instructional strategies, student engagement, and teaching effectiveness to address such questions as: How do the differences in linguistic structure between Spanish and English inform the design of instructional formats and strategies to teach literacy skills in the languages? Are instructional strategies that promote literacy development in English (for ELLs in English immersion programs) similar to those that promote literacy development in Spanish (for ELLs in primary language programs)? To address the second specific aim, we will investigate the extent to which ratios of Spanish to English, instructional strategies, student engagement, and teaching effectiveness relate to student oracy and literacy development. Finally, to address the third specific aim-teacher knowledge-participating teachers will be invited to collaborate in ongoing professional development that provides generic strategies as well as curriculum-specific strategies for teaching ELLs. Project III directly responds to the following questions in the RFA: What are the optimal instruction strategies that can facilitate the the transition from Spanish to English? Do variations in the degree of explicitness of reading instruction interact with information processing strengths and weaknesses? If so, are these variations different for Spanish and English?